The present invention relates generally to stratospheric transponder platform communications systems. More specifically, but without limitation thereto, the present invention relates to an architecture for communicating between a user terminal and multiple stratospheric transponder platforms.
In future stratospheric communications systems, it is expected that multiple stratospheric transponder platforms will be employed by several service providers to transmit communications signals using the same frequency band. The capability of a user terminal receiver on the ground to access different services from multiple stratospheric transponder platforms is important to the viability of the transponder platform system. Although a phased array antenna at the user terminal may be used to steer the beam from one stratospheric platform to another to avoid signal interference, such antennas are too expensive for the mass consumer market. Similarly, using separate antennas to track each stratospheric transponder platform is not practical for low cost terminals. A method is therefore needed for communicating between a user terminal and multiple stratospheric platforms using low cost antennas that do not require either a tracking mechanism or beam forming circuitry.